Means and method of antistroboscopic arc operation



Feb. 3, 1953 G. s. SPERTI v 2,627,591 MEANS AND METHOD OFANTISTROBOSCQPIC ARC OPERATION Filed June 2'7, 1944 i an 1 38 587 6o 59r4 44 4-11 H 50s.

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Patented Feb. 3, 1953 MEANS AND METHOD OF ANTISTROBO- SCOPIC ARCOPERATION George .S. Sperti, Burlington, Ky., assignor to InstitutumDivi Thomae Foundation, Cincinnati, Ohio, acorporation of OhioApplication June 2'1, 1944, Serial No. 542,368

12 Claims. (01. 315-99) My invention relates to the operation ofenclosed are devices, and in particular fluorescent lights. As is wellknown, in the operation of these lights a distinct stroboscopic effectis observed.

An object of this invention is the provision" of means and a method ofoperation in which the stroboscopic effect is greatly cut down orsubstantially eliminated. 1 a 1 Another object of the invention is theoperation of such devices at very much greater eniciencies than havehitherto been attainable.

Yet another object of the invention is the attainment of theseadvantages in the operation of light sources which,where desired, eithermay be of standard construction or if modified need be modified only inminor particulars, and, indeed, in the direction of simplification ofconstruction. These principal objects of the invention and others whichwill be set forth hereinafter, or will be apparent to one skilled intheart upon reading these specifications, I attain by those construe tionsand arrangements of parts and in those modes of operation of which Ishall now describe .certain exemplary embodiments- Reference is made tothe drawings which form a part hereof and in which:

Figure 1 is a diagrammatic representation ofa light source and circuitsfor high-voltage operation.

Figure 2 is a diagrammatic representation of a light source and circuitsfor three-phase operation.

Figure 3 is a diagrammatic representation of a light source and circuitsfor low voltage operation.

Figured is a partial circuit diagram showin another mode of securing ashift in phase.

Briefly, in the practice of my invention, I have found that it ispossible to provide an enclosed arc device havingtwo pairs of electrodesand to maintain arc discharges between the pairs of electrodes, 1. e.,an arc discharge between an e1ectrode of one pair and an electrode ofthe other,

. and another arc discharge between the other elec=- 'my enclosed arcstructure is similar to that of the familiar fluorescent tube andcomprises an elongatedenvelope having a pair of electrodes at each end,the envelope being evacuated and containing a small quantity of such asubstance as mercury. The envelope may also ifdesired, contain aquantity of noble gas.-' While the utility structures.

of my invention is not confined to fluorescent lights, such lights are aparticular field of utility for it, in which another advantage of myinvention is obtained. Whena structure such as that mentioned above isenergized inthe way hereinafter set forth, two arc-discharges aremaintained therein; but the illumination given on" by the fluorescent.coatingonthe envelope is much more thantwice the illumination"obtainable with a single are discharge. a

- While I do not wish to-be bound by theory, I explain this surprisingeffect as due to the very much more continuous activation of thefluorescent coating. Fluorescent coatings are not particularly efiicientin giving ofi-visible light when activated by ultra violet radiations,and their efficiency is diminished when the. activation laintermittent.When the activation becomes more nearly continuous, their eiiiciency isvery greatly increased. Hence, by my invention with the; form offluorescent light mentioned above, I amable to secure much more'thantwice the illumination from a single light source without theexpenditureof proportionate'energy.

Moreover, I have found that with thegtype of light sourceto :whichLhavereferred,- havinga pair of electrodes at each end, I can maintain thetwo are discharges between respective electrodes of each pair'withoutinterference ,and withoutsuch, cross fire between electrodes of eachpair, aswill give rise to any appreciable energy loss. v

In Figure l, I have shown at l, the envelope of a fluorescent tube whichenvelope-will be coated within with a suitable, fluorescent coating; Ateach end there is a press "2 or 3 through which pass leads terminatingin electrodes 4* andb for thepress 2, andt and 'i' f0l. the press lheform of these electrodes is not a limitation on my invention: and theymay take any convenient form, from bare wireszto more. elaborate Thearrangement shown in Figure 1 is intended for high-voltage operation;and while this is not in 'all:instances necessary, I prefer to have theelectrodesor portions thereof-{coated with an electronemissivesubstance. The electrodes become heated during the operation of thelight surface and an electron emissivecoating assists in the maintenanceof the arc discharges leads l2 and 3. The electrodes 4 and fi areconnec'ted by leads lt and to a secondary It of a transformer of whichthe primary H is connected across power leads i8 and I9. These powerleads may, of course, be the same as the power leads l2 and I3; and thetransformers, instead of being separate entities, may be combined in aSingle struc re Means. areg however, provided for applying. to oneelectrode of each pair an energizing voltage which is out of phase withthe energizing voltage applied to the other electrodes of each pair. -Ihave shown in Figure 1 a capacity g l eonnected in parallel with thesecondary I6 for this purpose. There are other ways of securing a shiftin voltage phase. In Figure-4 Iihavefshown afcapacity 2|, connected inseries "with'the sectindary l6. Rotary converters may also be employedfor this purpose if desired. In the operation of the arrangement ofFigure 1 an arc is struck between electrodes 5 and "l,

and another are is struck between electrodes '1 and 6; "but thelatterarc' 'is oiit {of phase with the former. The "sail-eats outphasinmay be consider'ably varied. The preferred c'ondition: is att'ai'nedwhen the two arc'sare 90} 'oiit offphase with each other, but lesserdegrees of ou't phasin'g a operativeand will greatly :cut down 'thestroboscopic eiT-e'ct s weu as? greatly increase the efil'oi ejricyfin-'{geriera-lfthe ent-phasing 'will be between say 60"and the idalof;90'.

is There is substantially no 'crdss fire -between elect'rodesl and 5 orbetween electrodes G and I. In Figure 2, Iihav'e shown a'fi'uorescentlight "soiirce 22, arranged forY' three -phase operation.

This light source lias atone and three electrodes,

23, 24 and -2-5,- an at theother end another three "electrodes '26, 2Tand' 28. fElectrodes- 25 and 28 are sl iown connected by'l'eads2'9a'nd'30, to one of *the se conda ries 3 I "of afthree phas etransformer.

The'electrodes-M and -21 areshown connected by leads 32 {;'a'nd 5!;3,to-another secondary 34 of the ;-transformer. I'h'e"electrodes 23 and 26are con-- -'-nected by leads 3513 1 {36 to a third secondary3'I,"-of"the transformer;- 'Thethree'primaries 38,

39 and 4!) are connected.t6gether, -'and" to"power leads '4 i ,42 and inthef'ordinary"three-phase bridge construction It will be noted that the3 three secondaries 31, 34 'and"'37 are not connected together as is[usual in three-phase transformers, but are'opierate'd as separatesecondaries. Three arcs-are thus maintainedfone between electrodes 23a'nd'26, and another between electrodes 24 and 21, and the third betweenelectrodes 25 -and 28. These are discharges" are substantially '60" outof 'phasew-ith each-other. r

1 In. Figure 3 -I-have .indicated diagrammatically Zthstandard-fluorescent light source 34 having at one end electrodes and46} and atthe other electrodes Hand '48. The' electrodes of each pair.however, are connected. together within themvelope :by. filamentsindicatedat 49 and 5B. These .filaments are coatediwithelectronemissivesubstance; andlthestructuresisone intended for lowvoltagepperation, The filaments are initially heatedanri the main'arc isstruck when the atmosphere within the light source has become.sufiiciently ionized, whereupon the filaments are usuall;y,tie-energized aspnderstood in this art.,, I

zhav sh wn lele tmdes stan .48 connected; b

leads 5!: andiz toa, se condary 53of a transformer of which the primary$415; conneotedsacross APQW L %?15 ;-5 .r? fi 5 Th e n 53 may {havethephase of deliyered voltage controlled 1-Wae'i ee ya T s ec m nd. a

.sll n-sqnneeted e. .si and 59 t a d ubl pore, double-throw switch'lil).When this switch is in the position shown in solid lines, the shortcircuitin element GI connects leads 58 and 59. This throws the filaments49 and 56 in series into the circuit of the secondary 53. The filamentsare energized and operate to ionize the atmosphere within the envelope,ultimately permitting an arc discharge'between electrodes 46 and 48.When this occurs "the switch 60 may be thrown to the position shown indotted lines, in .which position leads 59a and 59a act along with lea ds58 .and .59 to connect electrodes and 4'! f-a'c' ro'ss,' the"secondaryB2 of a transformer, the rimary E3 of which is connected across powerleads fidandfii, A second are therefore, is struck between electrodesand 41; and since the voltagents-verse by secondaries E2 and 53 are outof ,phase, this second arc discharge will be out of phase with the firstmentioned are discharge within the envelope, and the objects of myinvention are thus attained.

Again, the two transformers. may he builttogether as a, single unitandeither secondary may be, out-phased ,as respects the other. Othermodes of operation including the use of chokes and out-phasing] means;rotary converters and the like, may ,be' employed and ,willzbe withinthe skill of theworker in the art to apply in thelight of the teachingsherein. The switch Bllflrnay be arrangedfor automatic operation, as bythermostatic means or otherwise, as will be readily understood.

Modifications may be, made in my invention without departing from thespirit of it.

Having thus describedmyinvention in. certain exemplary embodiments, whatI ,claimas new and desire to secureby Letters Patent is:

1. In, astructure for,theipurposedescribed,Ha ingle,elongated'envelo'pe, fourelect'rodesin said envelope located in pairsadjacent, the; ends, of said elongated envelope, circuit meansforapplying an arcdischarge violtageito two of said electrodes, circuitImeans independentxof, the first mentioned circuit mea'nsfor applying.an are discharge voltage to the fother. two of said. electrodes,.saidcircuit means each being vconnectedlto an electrode of each pair sothat separate'arcfdischarges .occur inthe direction of, the length ofsaid elongated envelope, and means for ca'using said two are dischargevoltages to .be out of phase :with each other by substantially 60tolsubstantially whereby to minimize strobos'copic effects.

2. In a structure, for the purpose described, a single, elongatedenvel0p'e,,four electrodes 'inxsaid envelope located in pairs adjacentthe ends. of said elongated,enyelope,.,circ11it means for, ."applying'an arcjdischarge voltage to twodofiisaid elect'rodescircuit meansindependent? of the. first mentioned, circuit means for applyinglan arcdischarge voltage to the other two of said'elect'rodes, said circuitmeans each being, connected to an electrode of each pair, 50,- thatseparatel arc. discharges occur ,in the direction of the length. of saidelongated envelope, and means for:.causing said two arc.discharge'lvoltages to be outiof phase with eachother'by substantially6i)? tov substantially 90,whereby to minimize stroboscopic ,effects,said envelope haying acoating. offluorescent substance energized byirradiation from each arc discharge whereby theefiiciencyof lightemission from said fluorescent coating is greatly improved.

3. In combination, an arc dischargedevlce comprising a single elongatedenvelope haying a pair of "electrodes adjacent each'end thereof,

5 means for applying an arc discharge voltage to an electrode of eachpair, means independent of said first mentioned means for applying anarc discharge voltage to the other electrode of each pair, and means forcausing said discharge voltages to be out of phase with each other.

4. In combination, an arc discharge device comprising a single elongatedenvelope having a pair of electrodes adjacent each end thereof, meansfor applying an arc discharge voltage to an electrode of each pair,means independent of said first mentioned means for applying an arcdischarge voltage to the other electrode of each pair, and means forcausing said discharge voltages to be out of phase with each other, saidlast mentioned means comprising a means including inductance andcapacity for modifying the volt age phase of one of said voltageapplication means.

5. In combination, an arc discharge device comprising an envelope with apath of arc discharge therein, sets of electrodes at each end oi saidpath, each such set comprising three electrodes, a three-phasetransformer having primaries connected bridgewise to the power leads ofa three-phase power system, said transformer having separatesecondaries, each such secondary connected respectively to an electrodeof each set, so that each set of electrodes comprises respectiveelectrodes powered for are discharge by are discharge voltagessubstantially 60 out of phase with each other.

6. The structure claimed in claim 5 including a fluorescent coating onsaid envelope.

7. In combination, a light source comprising an elongated envelope, apair of electrodes at each end of an arc discharge path within saidenvelope, a filament associated with electron emlssive substanceconnecting the electrodes of each pair, means for applying power for aredischarge to one electrode of each pair, means for connecting togetherthe other electrodes of each pair, whereby to energize said filaments,and means for connecting said last mentioned electrodes to a source ofarc discharge power, said sources of arc discharge power arrangedindependently of each other to apply voltages to said electrodes whichare out of phase with each a other.

8. A method of operating arc discharge devices to diminish stroboscopiceffect, which method comprises providing an arc discharge device with anarc discharge path and a set of electrodes at each end of said path, andindependently power ing respective electrodes of each set so as toproduce along said path at least two are discharges which are out ofphase with each other.

9. A method of operating arc discharge devices to diminish stroboscopiceifect, which method comprises providing an arc discharge device with anarc discharge path and a set of electrodes at each end of said path, andindependently powering respective electrodes of each set so as toproduce along said path at least two are discharges which are out ofphase with each other, and locating a fluorescent coating so as to beactivated by all such are discharges.

10. The method of claim 8, wherein three elec trodes are provided ineach set, and the electrodes of each set are respectively powered byvoltages from a three-phase power supply, which voltages aresubstantially 60 out of phase with each other.

11. A method of operating fluorescent light sources having a pluralityof electrodes at each end, which comprises powering the electrodes ofsuch a fluorescent light source so as to produce therein separate arcdischarges following substantially the same path and which are betweensubstantially 60 and substantially 90 out oi phase with each other,whereby to diminish the stroboscopic effect and to increase theeficiency of visual light emission by more nearly continuouslyactivating the fluorescent means in said fluorescent light source.

12. A method of operating fluorescent light sources having an arcdischarge path and a pair of electrodes connected by filaments at eachend, which comprises first connecting together one electrode of eachpair and powering the other electrode of each pair, whereby to energizesaid filaments, thereafter breaking the connection between said firstmentioned electrodes and powering said first mentioned electrodesindependently with a Voltage which is out of phase with the voltage ofthe first mentioned powering step.

GEORGE S. SPERTI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,974,284 Lilienfeld Sept. 18,1934 2,206,701 Klemperer July 2, 1940 2,232,780 Foulke Feb. 25, 19412,264,055 Stocker Nov. 25, 1941 2,265,323 Spanner Dec. 9, 1941 2,301,671Abadie Nov. 10, 1942 2,354,654 Abbott Aug. 1, 1944 2,364,889 Blair Dec.12, 1944 FOREIGN PATENTS Number Country Date 861,198 France Oct. 22,1940

